Load dependent damper for a vehicle suspension system

ABSTRACT

A valve assembly for a vehicle suspension system includes a valve body, a first flow controller, a first plunger, a second flow controller, and a second plunger. The valve body defines a first inlet port, a first outlet port, a first chamber connected to the first inlet port and the first outlet port, a second chamber, a second inlet port, a second outlet port, a third chamber connected to the second inlet port and the second outlet port, and a fourth chamber. The first flow controller is positioned within the first chamber. The first plunger is positioned between the first chamber and the second chamber. The second flow controller is positioned within the third chamber. The second plunger is positioned between the third chamber and the fourth chamber.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/614,231, filed Jun. 5, 2017, which is a continuation of U.S.application Ser. No. 14/664,393, filed Mar. 20, 2015, which is acontinuation of U.S. application Ser. No. 13/830,808, filed Mar. 14,2013, all of which are incorporated herein by reference in theirentireties.

BACKGROUND

The present application relates to suspension systems for vehicles. Morespecifically, the present application relates to a load dependent damperfor a suspension system.

Dampers (e.g., dashpots, hydraulic shock absorbers, etc.) dissipatekinetic energy as part of a vehicle suspension system. Dampers ofteninclude a housing, end caps, a piston, and a rod that is coupled to thepiston. Energy is dissipated through a hydraulic fluid flow along ahydraulic circuit (e.g., between a first chamber within the housing anda second chamber within the housing). The piston includes a plurality oforifices that are covered with a shim stack (e.g., a plurality ofcompressed shims). As the piston translates through the housing,hydraulic fluid is forced from the first chamber, through the piston,and into the second chamber. Specifically, pressurized hydraulic fluidis forced through the orifices within the piston, deflects a portion ofthe shim stack to create an opening, and flows into the second chamberby passing through the opening.

Such traditional dampers provide a damping force that does not varybased on the weight of the vehicle. The characteristics of thesuspension system (e.g., the spring rate and damping rate) are tuned fora specific configuration. For example, a vehicle that is configured tocarry a heavy load may have a relatively stiff suspension system that iscapable of supporting the additional weight of the load. However, if theload is removed from the vehicle, the ride may be excessively stiff orover damped, thereby reducing ride quality for occupants of the vehicle.Conversely, if the suspension system is tuned for the unloadedcondition, the vehicle may have a relatively soft suspension system notsuited to support the additional weight in the loaded condition. By wayof example, such a vehicle may have a suspension that is under damped inthe loaded condition thereby reducing ride quality for occupants withinthe vehicle.

The suspension system may include a flow device coupled to anelectronically controlled actuator to compensate for fluctuations inload weight. For example, an electronic actuator may be used to open orclose one or more passages through a piston in the damper to adjust sizeor number of ports through which hydraulic fluid flows (e.g., bypassports, etc.) thereby changing performance. However, such an electronicsystem adds additional cost and complexity to the vehicle suspensionsystem. Further, the electronic components of the system (e.g., sensors,control modules, the actuator, etc.) may lack the appropriate level ofdurability to operate in adverse conditions.

SUMMARY

One embodiment relates to a valve assembly for a vehicle suspensionsystem. The valve assembly includes a valve body, a first flowcontroller, a first plunger, a second flow controller, and a secondplunger. The valve body defines a first inlet port, a first outlet port,a first chamber connected to the first inlet port and the first outletport, a second chamber, a second inlet port, a second outlet port, athird chamber connected to the second inlet port and the second outletport, and a fourth chamber. The first flow controller is positionedwithin the first chamber. The first plunger is positioned between thefirst chamber and the second chamber. The second flow controller ispositioned within the third chamber. The second plunger is positionedbetween the third chamber and the fourth chamber.

Another embodiment relates to valve assembly for a vehicle suspensionsystem. The valve assembly includes a valve body, a flow controller, anda plunger. The valve body defines an inlet port, an outlet port, a firstchamber connected to the inlet port and the outlet port, and a secondchamber. The flow controller is positioned within the first chamber. Theplunger includes a piston positioned within the second chamber, a rodextending from the piston into the first chamber, and an engagementmember coupled to the rod and positioned to variably engage the flowcontroller based on a pressure within the second chamber.

Yet another embodiment relates to valve assembly for a vehiclesuspension system. The valve assembly includes a valve body, a flowcontroller, and a plug. The valve body defines an inlet port, an outletport, a first chamber connected to the inlet port and the outlet port,and a second chamber. The flow controller is slidably positioned withinthe first chamber. The flow controller defines a passage. The plug isslidably positioned between the first chamber and the second chamber.The plug is spaced from the flow controller. A size of the passage and,therefore, a flow rate through the passage varies based on a position ofthe flow controller. A position of the plug is repositionable based on apressure within the second chamber. The position of the flow controlleris repositionable based on the position of the plug.

The invention is capable of other embodiments and of being carried outin various ways. Alternative exemplary embodiments relate to otherfeatures and combinations of features as may be recited in the claims.

BRIEF DESCRIPTION OF THE FIGURES

The disclosure will become more fully understood from the followingdetailed description, taken in conjunction with the accompanyingfigures, wherein like reference numerals refer to like elements, inwhich:

FIG. 1 is a perspective view of an axle assembly including a suspensionsystem, according to an exemplary embodiment.

FIG. 2 is a perspective view of a suspension system an axle assembly,according to an exemplary embodiment.

FIG. 3 is a partial schematic sectional view of a damper assembly,according to an exemplary embodiment.

FIG. 4A is a front elevation view of a damper assembly, according to anexemplary embodiment.

FIG. 4B is a rear elevation view of the damper assembly of FIG. 4A.

FIG. 5A is a front view of a valve block for a damper assembly,according to an exemplary embodiment.

FIG. 5B is a top view of the valve block of FIG. 5A.

FIG. 5C is a bottom view of the valve block of FIG. 5A.

FIG. 5D is a left side view of the valve block of FIG. 5A.

FIG. 6 is a sectional view of the valve block of FIG. 5D.

FIG. 7A is a detail sectional view of the valve block of FIG. 6.

FIG. 7B is a detail sectional view of the valve block of FIG. 6.

FIG. 8A is a front elevation view of a damper assembly, according to anexemplary embodiment.

FIG. 8B is a rear elevation view of the damper assembly of FIG. 8A.

FIG. 9A is a front view of a valve block for a damper assembly,according to an exemplary embodiment.

FIG. 9B is a left side view of the valve block of FIG. 9A.

FIG. 10 is a sectional view of the valve block of FIG. 9B.

FIG. 11A is a detail sectional view of the valve block of FIG. 10.

FIG. 11B is a detail sectional view of the valve block of FIG. 10.

FIG. 12A is a partial sectional view of the valve block of FIG. 10.

FIG. 12B is a partial sectional view of the valve block of FIG. 10.

FIG. 13A is a front elevation view of a damper assembly, according to anexemplary embodiment.

FIG. 13B is a top rear elevation view of the damper assembly of FIG.13A.

FIG. 13C is a bottom rear elevation view of the damper assembly of FIG.13A.

FIG. 14A is a front view of a valve block, according to an exemplaryembodiment.

FIG. 14B is a top view of the valve block of FIG. 14A.

FIG. 14C is a bottom view of the valve block of FIG. 14A.

FIG. 14D is a left side view of the valve block of FIG. 14A.

FIG. 14E is a rear view of the valve block of FIG. 14A.

FIG. 15A is a sectional view of the valve block of FIG. 14A.

FIG. 15B is a sectional view of the valve block of FIG. 14A.

FIG. 16A is a sectional view of the valve block of FIG. 14C.

FIG. 16B is a sectional view of the valve block of FIG. 14B.

FIG. 16C is a sectional view of the valve block of FIG. 14C.

FIG. 16D is a sectional view of the valve block of FIG. 14C.

FIG. 17 is an elevation view of a pair of cross-plumbed dampers,according to an exemplary embodiment.

DETAILED DESCRIPTION

Before turning to the figures, which illustrate the exemplaryembodiments in detail, it should be understood that the presentapplication is not limited to the details or methodology set forth inthe description or illustrated in the figures. It should also beunderstood that the terminology is for the purpose of description onlyand should not be regarded as limiting.

According to the exemplary embodiments shown in FIGS. 1-17, a damper fora vehicle suspension system includes a mechanical system for varying thedamping characteristics of the damper in response to different loadsapplied to the vehicle suspension system. By varying the dampingcharacteristics of the damper for different load conditions, the damperis intended to improve ride quality for occupants of the vehiclerelative to traditional dampers that are tuned to a static, compromiseddamping level.

Referring to the exemplary embodiment shown in FIG. 1, an axle assembly110 is configured to be included as part of a vehicle. The vehicle maybe a military vehicle, a utility vehicle (e.g., a fire truck, a tractor,construction equipment, a sport utility vehicle, etc.), or still anothertype of vehicle. As shown in FIG. 1, axle assembly 110 includes adifferential 112 coupled to a half shaft 114. As shown in FIG. 1, halfshaft 114 is coupled to a wheel-end assembly 116. The wheel-end assembly116 may include brakes, a gear reduction, steering components, a wheelhub, a wheel, a tire, and other features. According to an exemplaryembodiment, the differential 112 is configured to be coupled with adrive shaft of the vehicle. Such a differential 112 may receiverotational energy from a prime mover (e.g., a diesel engine, a gasolineengine, an electric motor, etc.) of the vehicle. The differential 112then allocates torque provided by the prime mover between the halfshafts 114 of the axle assembly 110. The half shafts 114 deliver therotational energy to each wheel-end assembly 116. According to analternative embodiment, each wheel-end assembly 116 includes a primemover (e.g., the axle assembly 110 includes electric motors that eachdrive one wheel).

According to an exemplary embodiment, the axle assembly 110 includes asuspension system 118 that couples the chassis of the vehicle towheel-end assembly 116. In some embodiments, the chassis includes a pairof opposing frame rails, and the suspension system 118 engages theopposing frame rails through side plate assemblies. In otherembodiments, the chassis is a hull, a capsule, or another type ofstructural member. According to an exemplary embodiment, the suspensionsystem 118 includes a spring, shown as gas spring 120, and a damper,shown as hydraulic damper 122. As shown in FIG. 1, the gas spring 120and the hydraulic damper 122 are coupled in parallel to a lower supportmember, shown as lower swing arm 126. According to an exemplaryembodiment, the wheel-end assembly 116 is coupled to lower swing arm 126and an upper support member, shown as upper swing arm 124.

According to an exemplary embodiment, the vehicle is configured foroperation on both smooth (e.g., paved) and uneven (e.g., off-road,rough, etc.) terrain. As the vehicle travels over uneven terrain, theupper swing arm 124 and the lower swing arm 126 guide the verticalmovement of the wheel-end assembly 116. A stop, shown as cushion 128,provides an upper bound to the movement of the wheel-end assembly 116.It should be understood that axle assembly 110 may include similarcomponents (e.g., wheel-end assemblies, suspension assemblies, swingarms, etc.) for each of the two opposing lateral sides of a vehicle.

Referring next to the exemplary embodiment shown in FIG. 2, thesuspension system 118 includes various components configured to improveperformance of the vehicle. As shown in FIG. 2, gas spring 120 is a highpressure gas spring. According to an exemplary embodiment, thesuspension system 118 includes a pump, shown as high pressure gas pump130, that is coupled to gas spring 120. In some embodiments, suspensionsystem 118 includes a plurality of high pressure gas pumps 130 eachcoupled to a separate gas spring 120. In other embodiments, thesuspension system 118 includes fewer high pressure gas pumps 130 thangas springs 120. According to an exemplary embodiment, the gas springand the pump include gas made up of at least 90% inert gas (e.g.,nitrogen, argon, helium, etc.). The gas may be stored, provided, orreceived in one or more reservoirs (e.g., tank, accumulators, etc.).During operation, the high pressure gas pump 130 selectively providesgas, under pressure, to at least one of the gas spring 120 and thereservoir. In some embodiments, at least one of the gas springs 120 andthe hydraulic dampers 122 receive and provide a fluid (e.g., gas,hydraulic fluid) to lift or lower the body of the vehicle with respectto the ground thereby changing the ride height of the vehicle.

According to the exemplary embodiment shown in FIG. 3, a damper assembly200 includes a damper, shown as a hydraulic damper 202. The hydraulicdamper 202 includes a tubular (e.g., cylindrical, etc.) sidewall, shownas a housing 204, and a pair of end caps 206 and 208 to define an innervolume. The inner volume of the hydraulic damper 202 is separated intoan extension chamber, shown as a first chamber 210, and a compressionchamber, shown as a second chamber 212. The chambers 210 and 212 areseparated by a piston, shown as a plunger 214, that is slidable withinthe inner volume of the hydraulic damper 202. Translation of the plunger214 within the hydraulic damper 202 increases or decreases the volume ofthe first chamber 210 and the second chamber 212. Such translationforces hydraulic fluid out of the first chamber 210 through a port 218or out of the second chamber 212 through a port 216.

As shown in FIG. 3, the damper assembly 200 includes a valve block,shown as valve assembly 220, coupled to the hydraulic damper 202. Thevalve assembly 220 includes a main body 222 that forms a pair of fluidpaths 224 a and 224 b (e.g., flow paths, fluid circuits, etc.). Thefirst fluid path 224 a extends from an inlet opening 226 a to an outletopening 228 a. The second fluid path 224 b extends from an inlet opening226 b to an outlet opening 228 b. With the valve assembly 220 coupled tothe hydraulic damper 202, the inlet openings 226 a and 226 b are influid communication with the port 216 and the port 218, respectively.According to the exemplary embodiment shown in FIG. 3, the inletopenings 226 a and 226 b are aligned with and directly abut the ports216 and 218. According to an alternative embodiment, the openings 226 aand 226 b may be otherwise coupled to the ports 216 and 218 (e.g., withan intermediate hose, pipe, tube, etc. extending between the hydraulicdamper 202 and the valve assembly 220).

According to the exemplary embodiment shown in FIG. 3, a flow controllerincludes a shim stack 230 coupled to a piston 232. According to anexemplary embodiment, the flow controller is provided along each of thefluid paths 224 a and 224 b to regulate the flow of hydraulic fluidalong the fluid paths 224 a and 224 b and thereby regulate the flow ofhydraulic fluid out of the first chamber 210 and the second chamber 212of the hydraulic damper 202.

The piston 232 is coupled to the main body 222 and the shim stack 230 iscoupled to the piston 232 (e.g., with a bolt). The piston 232 includes aplurality of passages or orifices that are covered by the shim stack230. Energy is dissipated as pressurized hydraulic fluid is forcedthrough orifices in the piston 232 thereby deflecting a portion of theshim stack 230 to create an opening through which the pressurizedhydraulic fluid to flows. The hydraulic fluid may then pass around theedges of the shim stack 230 and out of the valve assembly 220 throughthe outlet opening 228 a or 228 b. The shim stack 230 in each of thefluid paths 224 a and 224 b may have different characteristics (e.g.,thickness, stiffness, diameter, number of individual shims, etc.) suchthat the damping characteristics of each flow controller is different.According to an exemplary embodiment, the shim stack 230 is a pyramidformed by a stack of individual shims. By way of example, the diametersof the individual shims may decrease from a first shim having a largestdiameter positioned at one end to a final shim having a smallestdiameter positioned at an opposing end. The individual shim stack havingsmaller diameters may adjust the spring rate of the individual shimhaving a larger diameter thereby changing the damping characteristics ofthe flow controller.

According to an exemplary embodiment, a reservoir is coupled to anauxiliary port 234 of valve assembly 220. As shown in FIG. 3, theauxiliary port 234 is in fluid communication with at least one of thefluid paths 224 a and 224 b. The reservoir includes a pressurized fluid(e.g., nitrogen gas) that interfaces with the hydraulic fluid disposedwithin valve assembly 220. The hydraulic fluid within valve assembly 220may cavitate (e.g., foam) thereby altering the damping characteristicsof the valve assembly 220. According to an exemplary embodiment,pressurized fluid from the reservoir reduces cavitation.

According to an exemplary embodiment, a load dependent force (e.g.,pre-load, biasing force, pilot force, offset force, etc.) modifies thedamping characteristics of the shim stack 230. The load dependent forcevaries with the load on the vehicle suspension system. According to anexemplary embodiment, the load dependent force varies with the pressureof a high pressure gas, such as a high pressure gas from a gas spring(e.g., the gas spring 120 of the suspension system 118). When anincreased load is applied to the vehicle suspension system (e.g., byadding a payload weight to a sprung weight of the vehicle), the pressureof the gas increases and an increased force is applied to the flowcontroller. The increased force reduces the flow rate of hydraulic fluidthrough the flow controller thereby changing the characteristics (e.g.,flow rate) of fluid from the first chamber 210 and the second chamber212. The damping characteristics of the damper assembly 200 aretherefore increased for a stiffer suspension. Conversely, if the load onthe vehicle suspension system is reduced (e.g., a payload is removed,etc.), the pressure of the gas decreases and a reduced force is appliedto the flow controller. The reduced force increases the flow rate ofhydraulic fluid through the flow controller thereby changing thecharacteristics (e.g., flow rate) of fluid from the first chamber 210and the second chamber 212. The damping forces of the damper assembly200 are therefore decreased for a softer suspension.

According to the exemplary embodiment shown in FIG. 3, the loaddependent force is transmitted to the shim stack 230 through a piston,shown as plunger 240, coupled to the flow controllers inside the mainbody 222. Each of the plungers 240 include a first end 242 (e.g., pilotend) disposed in a spring pilot chamber, shown as a first chamber 244,and a second end 246 (e.g., interface end) disposed in a second chamber248. The second end 246 is a cup-shaped (e.g., bell-shaped, etc.)structure with an annular end face, shown as rim 250 that contacts theouter periphery of the shim stack 230. The plunger 240 slidably engagesthe walls of the first chamber 244, according to an exemplaryembodiment. A sealing member (e.g., a gasket, an o-ring, etc.) iscoupled to the plunger 240 and the main body 222 such that the firstchamber 244 is sealed from the second chamber 248.

The first chamber 244 is in fluid communication with a pressure source,such as a high pressure gas spring. According to an exemplaryembodiment, the first chambers 244 are in fluid communication with oneanother and are supplied with a pressurized gas through a spring pilot,shown as pilot port 245. According to an alternative embodiment, thefirst chambers are not in fluid communication with one another and mayeach include a separate spring pilot supplying a pressurized gas (e.g.,at the same pressure, at a different pressure, etc.). The pressure inthe first chamber 244 acts on the area of the first end 242 of theplunger 240 to force the rim 250 against a face of the shim stack 230with a force (e.g., pre-load, biasing force, pilot force, offset force,etc.) that varies with the pressure of the fluid in the first chamber244. As the pressure in the first chamber 244 varies, the force withwhich the rim 250 of the plunger 240 engages the shim stack 230 varies,thereby varying the flow rate of fluid through the flow controller alongthe fluid paths 224 a and 224 b. By way of example, the pressure withinfirst chamber 244 may change with the pressure within a high pressuregas spring (e.g., due to a change in load applied to the vehiclesuspension). The magnitude of the force applied to the shim stack 230 bythe plunger 240 may be tuned in various ways. According to an exemplaryembodiment, the force is tuned by changing the relative diameters of thefirst end 242 and the second end 246 of the plunger 240 or by alteringthe contact area between the plunger 240 and the shim stack 230. Itshould be understood that the location of the applied force on the shimstack 230 changes the damping characteristics of the flow controller.According to an exemplary embodiment, the plunger 240 interfaces with anouter periphery of the shim stack thereby magnifying the change indamping characteristics produced by a change in pressure within firstchamber 244.

Referring next to the exemplary embodiment shown in FIGS. 4A-7B, adamper assembly 300 includes a damper, shown as a hydraulic damper 302.As shown in FIG. 4A, the hydraulic damper 302 includes a tubular (e.g.,cylindrical, etc.) sidewall, shown as a housing 304 and a pair of caps306 and 308. The housing 304 and the caps 306 and 308 define an innervolume. The inner volume of the hydraulic damper 302 is separated into afirst chamber (e.g., compression chamber, jounce chamber, etc.) and asecond chamber (e.g., extension chamber, rebound chamber, etc.). Thechambers are separated by a piston that is slidably positioned withinthe inner volume of the hydraulic damper 302. Translation of the pistonwithin the hydraulic damper 302 increases or decreases the volume of thefirst chamber and the second chamber, thereby forcing hydraulic fluidflow along hydraulic circuits through a first port and a second port,respectively. According to an exemplary embodiment, the first port andthe second port are provided in the cap 306. According to an alternativeembodiment, one or both of the first port and the second port areprovided in the cap 308.

As shown in FIGS. 4A-7B, the damper assembly 300 further includes avalve block, shown as valve assembly 320, coupled to the hydraulicdamper 302. The valve assembly 320 includes a pair of inlet ports 326 aand 326 b, as shown in FIG. 5C. With the valve assembly 320 coupled tothe hydraulic damper 302, the inlet openings 326 a and 326 b are influid communication with the first chamber and the second chamber.According to the exemplary embodiment shown in FIGS. 4A and 4B, thevalve assembly 320 is coupled to the cap 306 of the hydraulic damper 302such that the inlet openings 326 a and 326 b are aligned with anddirectly abut the first port and second port of the hydraulic damper302. According to an alternative embodiment, the openings 326 a and 326b are otherwise coupled to the first port and second port of thehydraulic damper 302 (e.g., with a hose, tube, pipe, etc. extendingbetween the hydraulic damper 302 and the valve assembly 320). As shownin FIGS. 4A-5D, the valve assembly 320 includes a pair of outletopenings coupled to outlet fittings 328 a and 328 b.

Referring to FIG. 6, the body 322 forms a pair of fluid paths 324 a and324 b (e.g., flow paths, fluid circuits, etc.). The first fluid path 324a extends from the inlet opening 326 a to the outlet fitting 328 a. Thesecond fluid path 324 b extends from the inlet opening 326 b to theoutlet fitting 328 b. While the flow controller positioned along secondfluid path 324 b is detailed herein, it should be understood that asimilar flow controller is positioned along first fluid path 324 a.

According to an exemplary embodiment, valve assembly 320 includes a flowcontroller. As shown in FIGS. 6 and 7A, the flow controller includes ashim stack 330 coupled to a piston 332. According to an exemplaryembodiment, a flow controller is provided along each of the fluid paths324 a and 324 b to regulate the flow of hydraulic fluid through thefluid paths 324 a and 324 b. Such flow controllers provide dampingforces for the damper assembly 300, according to an exemplaryembodiment.

As shown in FIGS. 6 and 7A, the piston 332 includes a plurality ofpassages 333 that are covered by the shim stack 330. According to anexemplary embodiment, the shim stack 330 is coupled to the piston 332with a washer 335 and a bolt 334 that engages a diffuser 336 (e.g., witha threaded connection). The diffuser 336 is coupled to an interior wallof the body 322 such that the shim stack 330, the piston 332, and thediffuser 336 are fixed relative to the body 322. The bolt 334 couplesthe center of the shim stack 330 to the piston 332, allowing the outeredges of the shim stack 330 to flex relative to the piston 332.

Hydraulic fluid enters the valve assembly 320 from the hydraulic damper302 (e.g., from either the first chamber or the second chamber) througheither of the inlets 326 a or 326 b. The fluid passes into an inletchamber 337, through a plurality of passages 338 in the diffuser 336,and into an intermediate chamber 339 between the diffuser 336 and thepiston 332. Energy is dissipated as pressurized hydraulic fluid isforced through passages 333 in the piston 332, deflecting the edges 331of the shim stack 330 to create an opening between the outer peripheryof the shim stack 330 and the piston 332. The hydraulic fluid then flowsaround the edges 331 of the shim stack 330 and out of the valve assembly320 through the outlet openings and the outlet fittings 328 a or 328 b.

The shim stack 330 in each of the fluid paths 324 a and 324 b may havedifferent characteristics (e.g., thickness, stiffness, diameter, numberof individual shims, etc.) such that the thereby differentially dampingfluid flow along the fluid paths 324 a and 324 b. According to anexemplary embodiment, the pistons 332 include a check valve mechanismpreventing fluid from flowing in a reverse direction along the fluidpaths 324 a and 324 b across the pistons 332.

According to an exemplary embodiment, a load dependent force (e.g.,pre-load, biasing force, pilot force, offset force, etc.) modifies thedamping characteristics of the shim stack 330. The load dependent forcevaries with the load on the vehicle suspension system. According to anexemplary embodiment, the load dependent force varies with the pressureof a high pressure gas, such as a high pressure gas from a gas spring(e.g., the gas spring 120 of the suspension system 118). According tothe exemplary embodiment shown in FIG. 6, the load dependent force actson each of the shim stacks 330 through a piston, shown as plunger 340.The plunger 340 includes a first end 342 (e.g., pilot end) disposed in aspring pilot chamber, shown as a first chamber 344, and a second end 346(e.g., interface end) disposed in a second chamber 348. The second end346 includes a cup, shown as a contact member 350, that has an end,shown as rim 352. As shown in FIGS. 6 and 7A, the rim 352 contacts theouter periphery of the shim stack 330. According to an exemplaryembodiment, the rim 352 has a rounded edge to facilitate the deflectionof the edges of the shim stack 330 away from the piston 332 and aroundthe rim 352.

The first chamber 344 is sealed from the second chamber 348 by a divider354 coupled to the body 322. According to an exemplary embodiment, thedivider 354 engages an interior wall of the body 322 with a threadedconnection. According to an exemplary embodiment, a sealing member,shown as an o-ring 356, is provided between the divider 354 and the body322.

Referring now to FIG. 7B, the first end 342 of the plunger 340 includesa piston 360. According to an exemplary embodiment, the piston 360slidably engages the interior walls of the body 322 and separates thefirst chamber 344 from a vent chamber 365 with a sealing member disposedin a groove 362. The first chamber 344 is in fluid communication with apressurized gas source (e.g., a high pressure gas spring). According toan exemplary embodiment, the first chambers 344 are each supplied withpressurized gas through a separate spring pilot, shown as pilot port345. According to an alternative embodiment, each of the first chambers344 is in fluid communication with one another and may be supplied witha pressurized gas through a common pilot port. The high pressure gasacts on the end surface 364 of the piston 360, forcing the pistontowards a vent chamber 365. A resilient member, shown as a stack ofBelleville washers 366, is provided within the vent chamber 365. Asshown in FIG. 7B, the Belleville washers 366 are compressed between thepiston 360 and a shoulder 368 of the body 322.

According to an exemplary embodiment, the valve assembly 320 includes abuffer, shown as insert 370. As shown in FIG. 7B, insert 370 is providedbetween the pilot port 345 and the first chamber 344. Pressurized gaspasses into the insert 370 from the pilot port 345 and thereafter flowsto the first chamber through a narrow passage 372 that is formed betweenthe insert 370 and the body 322. According to an exemplary embodiment,the insert 370 includes a male thread, and the body 322 includes afemale thread. At least one of the male thread of the insert 370 and thefemale thread of the body 322 includes a truncated tooth height (e.g.,the tip of the thread tooth is removed) to form the narrow passage 372.The truncated tooth forms a helical passage through which pressurizedgas may pass from the pilot port 445, around the insert 460, and intothe spring chamber 444. The narrow passage 372 has a relatively smalldiameter and is resistant to rapid flow of pressurized gas. The narrowpassage 372 buffers the flow therethrough such that the first chamber344 is partially isolated from transient spikes or drops in pressurewithin first chamber 344. Such a spike or drop in pressure may occur,for example, if the high pressure gas spring is suddenly compressed orextended (e.g., when the vehicle engages a positive or negativeobstacle, etc.). In other embodiments, the narrow passage 372 may beotherwise formed. According to an alternative embodiment, the firstchamber 344 is partially isolated from the high pressure gas source byanother mechanism (e.g., a long and slender capillary tube, etc.)coupled to the valve assembly 320.

According to an exemplary embodiment, the force generated by thepressure of the high pressure fluid acting on the end surface 364 of thepiston 360 forces the plunger toward the shim stack 330. The force ofthe pressurized gas on the end surface 364 of the piston is opposed by aforce (e.g., a smaller force) from the Belleville washers 366. In someembodiments, the range of pressures provided by a high pressure springis different than the preferred pressure range that imparts preferredloading forces on the shim stack 330. According to an exemplaryembodiment, the Belleville washers provide an offset force to tune thevalve assembly 320 such that the range of pressures provided by the highpressure spring more appropriately corresponds to a preferred range offorces applied to the shim stack 330.

The piston 360 at the first end 342 of the plunger 340 is rigidlycoupled to the contact member 350 at the second end 346 of the plunger340 with a rod 380. The rod 380 extends from the vent chamber 365,through the Belleville washers 366, and through a sealed opening in thedivider 354 (e.g., separator, cap, plug, etc.) into the second chamber348. The divider 354 separates the second chamber 348 from the ventchamber 365 and contains the hydraulic fluid within the second chamber348. The end of the rod 380 is coupled to the contact member 350 (e.g.,with a washer 384 and a nut 386, etc.). The bolt 334 and the washer 335are received in the hollow interior 355 of the contact member 350.Hydraulic fluid is able to flow into and out of the interior 355 throughopenings 358 in the contact member 350, preventing a pressuredifferential that may otherwise develop between the exterior and theinterior of the contact member 350.

As shown in FIG. 7A, the second end 346 of the plunger 340 imparts a netforce on the shim stack 330. According to an exemplary embodiment, thenet force (e.g., pre-load, biasing force, pilot force, offset force,etc.) is the difference between the force generated by the pressure ofthe high pressure fluid acting on the end surface 364 of the piston 360and the opposing force applied to the piston 360 by the Bellevillewashers 366. The net force is transferred through the rod 380 to contactmember 350. The rim 352 of the contact member 350 engages an outerperiphery of the shim stack 330. According to an exemplary embodiment,applying the net force at the outer periphery of the shim stack 330magnifies a change in damping characteristics (e.g., relative toapplying the net force radially inward more near a centerline).

As the pressure in the first chamber 344 varies (e.g., due to a changein pressure within a high pressure gas spring from a change in load),the force generated by the pressure of the high pressure fluid acting onthe end surface 364 of the piston 360 also varies. Such a variationchanges the net force with which the contact member 350 engages the shimstack 330, thereby varying the flow rate of fluid through the flowcontroller along the fluid path 324. The ratio of the magnitude of theforce applied to the shim stack 330 by the plunger 340 to the pressureof the pressurized gas in the first chamber 344 may be tuned by changingvarious characteristics. According to an exemplary embodiment, the ratiois tuned by altering at least one of the diameters of the end surface364 of the piston 360, the spring properties or number of the Bellevillewashers 366, and the contact area between the plunger 340 and the shimstack 330.

Referring next to the exemplary embodiment shown in FIGS. 8A-12B, adamper assembly 400 includes a damper, shown as a hydraulic damper 402.The hydraulic damper 402 includes a tubular (e.g., cylindrical, etc.)sidewall, shown as a housing 404, and a pair of caps 406 and 408. Thehousing 404 and the caps 406 and 408 define an inner volume. The innervolume of the hydraulic damper 402 is separated into a first chamber(e.g., compression chamber, jounce chamber, etc.) and a second chamber(e.g., extension chamber, rebound chamber, etc.). The chambers areseparated by a piston that is slidable within inner volume of thehydraulic damper 402. Translation of the piston within the hydraulicdamper 402 increases or decreases the volume of the first chamber andthe second chamber, forcing hydraulic fluid along hydraulic circuitsthrough a first port and a second port that are coupled to the firstchamber and the second chamber, respectively. According to an exemplaryembodiment, the first port and the second port are provided in the cap406. According to an alternative embodiment, one or both of the firstport and the second port are provided in the cap 408.

As shown in FIGS. 8A-12B, the damper assembly 400 includes a valveblock, shown as a valve assembly 420, coupled to the hydraulic damper402. The valve assembly 420 includes a pair of inlet ports 426 a and 426b. With the valve assembly 420 coupled to the hydraulic damper 402, theinlet openings 426 a and 426 b are in fluid communication with the firstport and the second port of the hydraulic damper 402. According to theexemplary embodiment shown in FIGS. 8A and 8B, the valve assembly 420 iscoupled to the cap 406 of the hydraulic damper 402 such that the inletopenings 426 a and 426 b are aligned with and directly abut the firstport and second port of the hydraulic damper 402. According to analternative embodiment, the openings 426 a and 426 b may be otherwisecoupled to the first port and second port of the hydraulic damper 402(e.g., with a conduit, hose, tube, pipe, etc. extending between thehydraulic damper 402 and the valve assembly 420). As shown in FIGS.8A-8B, the valve assembly 420 further includes a pair of outlet ports428 a and 428 b. In some embodiments, a plurality of damper assemblies400 (e.g., a pair) may be positioned on an axle, and the outlet ports428 a and 428 b of a first damper assembly 400 may be cross plumbed withthe opposite outlet ports 428 a and 428 b of a second damper assembly.

Referring to FIG. 10, the body 422 defines a pair of fluid paths 424 aand 424 b (e.g., flow paths, fluid circuits, etc.). According to anexemplary embodiment, the first fluid path 424 a extends from the inletopening 426 a to the outlet fitting 428 a. The second fluid path 424 bextends from the inlet opening 426 b to the outlet fitting 428 b. Thefirst fluid path 424 a and the second fluid path 424 b each extendthrough a sleeve 423 coupled to the body 422.

As shown in FIG. 10, the valve assembly 420 includes a flow controller,shown as a variable flow orifice, that includes a gate, shown as a gate430, positioned within the sleeve 423. While not detailed herein, itshould be understood that a second flow controller is similarlypositioned along the second fluid path 424 b. A variable flow orificedifferentially restricts the flow of hydraulic fluid through the fluidpaths 424 a and 424 b.

Hydraulic fluid enters the valve assembly 420 from the hydraulic damper402 (e.g., from either the first chamber or the second chamber) througheither of the inlets 426 a or 426 b. The fluid passes into an inletchamber 439 and then through a plurality of passages 437 in the insert436 coupled to the sleeve 423. The gate 430 includes a hollow portionformed by a tubular sidewall, shown as tubular sidewall 432, thatreceives a protruding portion 438 of the insert 436. The hydraulic fluidpasses through the insert 436 and engages an annular end surface of rim433 of the tubular sidewall 432. As shown in FIG. 11B, the tubularsidewall 432 defines an aperture, shown as opening 434, and the sleeve423 defines a passage interface 425 (e.g., an edge of sleeve 423adjacent the opening 434). According to an alternative embodiment, thegate 430 is a solid piston that is displaced by a pressure from thehydraulic fluid that interfaces with an end face to produce the force.The variable flow orifice may be formed by displacement of the gate 430,which exposes a passage in the sleeve 423 (e.g., having a rectangular,triangular, ovular, etc. shape).

According to an exemplary embodiment, the pressure of the hydraulicfluid engages the annular end surface of rim 433 and generates a force(e.g., in a direction along the length of tubular sidewall 432 and awayfrom inlet chamber 439). The force generated by the pressure of thehydraulic fluid overcomes a biasing force and displaces the gate 430away from the insert 436 until the opening 434 formed in the tubularsidewall 432 extends along the passage interface 425 of the sleeve 423.According to an exemplary embodiment, the variable flow orifice isformed by the portion of the opening 434 through which hydraulic fluidflows. Energy is dissipated and a damping force is generated aspressurized hydraulic fluid is forced through the variable flow orificeformed by the opening 434 and the passage interface 425. According to analternative embodiment, the variable flow orifice is formed by a channeldefined within sleeve 423 and a portion of the tubular sidewall 432(i.e. sleeve 423 may alternatively define the opening through whichfluid flows). According to still another alternative embodiment, thevariable flow orifice is formed by an aperture defined within tubularsidewall 432 and by a channel defined within sleeve 423.

According to the exemplary embodiment shown in FIG. 12A, the opening 434is triangularly shaped and extends between a narrow end 431 and a wideend 435. A slight overlap between the narrow end 431 of the opening 434and the passage interface 425 generates an aperture with a minimal areathat provides a greatest level of fluid damping. Additional displacementof the gate 430 results in a larger overlap between the opening 434 andthe passage interface 425 until the wide end 435 of the opening 434 ispositioned along the passage interface 425 such that the entire opening434 overlaps the passage interface 425. Such a position of gate 430generates an aperture with a larger area that allows more fluid to flowtherethrough and provides a reduced level of fluid damping. According toother exemplary embodiments, the opening 434 may be reversed such thatthe wide end 435 initially overlaps the passage interface 425. Accordingto the alternative embodiment shown in FIG. 12B, the opening istrapezoidally shaped thereby providing a different response curve ofdamping forces as a function of gate displacement. According to otherexemplary embodiments, the opening may be otherwise shaped (e.g.,semi-circular, oval, etc.) to provide still other response curves. Asshown in FIGS. 12A and 12B, the tubular sidewall 432 defines a singleopening 434. According to an alternative embodiment, the tubularsidewall 432 defines a plurality of openings 434 (e.g., having the sameshape, having the same size, having different shapes or sizes, etc.).

Referring again to FIGS. 10-11B, the displacement of the gate 430 isresisted by a biasing force. According to an exemplary embodiment, thegate 430 includes a piston 440 that is coupled to the tubular sidewall432. The piston 440 slidably engages the interior walls of the sleeve423 and separates an inner volume of the body 422 into a second chamber448 containing the hydraulic fluid and an intermediate chamber 446(e.g., spring chamber, buffer chamber, etc.). A sealing member disposedwithin a groove 441 may restrict fluid flow between the piston 440 andthe interior walls of the sleeve 423. As shown in FIGS. 10 and 11A,valve assembly 420 includes a plug, shown as plug 450, disposed on theopposite end of the intermediate chamber 446. The plug 450 slidablyengages the interior walls of the sleeve 423 and separates theintermediate chamber 446 from a spring chamber 444. A sealing memberdisposed within grooves 451 and 452 prevents fluid from seeping betweenthe plug 450 and the interior sidewalls of sleeve 423.

The intermediate chamber 446 is in fluid communication with apressurized gas source. According to the exemplary embodiment shown inFIGS. 9A-10, the intermediate chamber 446 is supplied with pressurizedgas through a port 447. The intermediate chamber 446 is charged to aspecified pressure (e.g., with nitrogen gas). According to an exemplaryembodiment, the intermediate chamber 446 has a pressure of betweenapproximately 200 psi and 300 psi. The pressurized gas acts on the endface 442 of the piston 440 to provide a biasing force to the gate 430.According to an alternative embodiment, the intermediate chamber 446 mayhouse another biasing member (e.g., a coil spring, a stack of Bellevillewashers, an elastomeric member) to provide a biasing force acting uponthe piston 440.

Referring to FIG. 11A, the plug 450 includes a first end 454 and asecond end 456. As shown in FIG. 11A, the spring chamber 444 is in fluidcommunication with a pressurized gas source (e.g., a chamber of a highpressure gas spring), and the first end 454 interfaces with the springchamber 444. According to an exemplary embodiment, the spring chambers444 are supplied with pressurized gas through a spring pilot 445.According to an alternative embodiment, each of the spring chambers 444include a separate spring pilot (e.g., to facilitate differentialpressures and resulting forces applied to different gates).

An insert 460 is received into the sleeve 423 and includes a centralbore that slidably receives the first end 454 of the plug 450. Passages462 extend through the insert 460 between the pilot port 445 and thespring chamber 444. The pressurized gas within the spring chamber 444engages an end face 455 of the first end 454 with a first pressure andgenerates a force on plug 450. The pressurized gas of the intermediatechamber 446 engages an end face 457 of the second end 456 with a secondpressure and generates an opposing force on plug 450. According to anexemplary embodiment, the first pressure is greater than the secondpressure. According to an exemplary embodiment, the cross-sectional areaof the end face 457 is greater than the cross-sectional area of the endface 455.

It should be understood that changing the pressure within spring chamber444 (e.g., the high pressure spring may compress and provide a higherpressure fluid to spring chamber 444) changes the forces imparted ongate 430. The plug 450 disposed between the spring chamber 444 and theintermediate chamber 446 provides an intermediate ratio to tune theforce applied onto gate 430. By way of example, the range of pressureswithin a high pressure gas spring (e.g., between the loaded and unloadedconditions) may be wider or narrower than a range of pressures thatcorresponds to a preferred range of forces applied to gate 430. In someembodiments, the forces imparted on gate 430 are further tuned with theratio of the areas of the end faces 455 and 457. According to anexemplary embodiment, the force applied to the gate 430 is a function ofthe spring pressure in the spring chamber 444, the ratio of the areas ofthe end faces 455 and 457, and the initial pressure of the gas in theintermediate chamber 446. The use of the intermediate chamber 446 allowsa non-linear biasing force to be applied to the gate 430.

According to an exemplary embodiment, the intermediate chamber isinitially charged with a pressurized fluid and the plug 450 is initiallyin a state of equilibrium. As the pressure of the fluid within springchamber 444 increases (e.g., due to a payload weight added to the sprungweight of the vehicle) the force on plug 450 increases therebycompressing the fluid within intermediate chamber 446. The increasedpressure within the intermediate chamber 446 engages the end face 442 ofpiston 440 thereby generating a greater force that biases the gate 430toward insert 436. According to an exemplary embodiment, the position ofthe gate 430 is related to the pressure within the spring chamber 444,the pressure within the intermediate chamber 446, the cross-sectionalareas of the first end 454 and the second end 456 of the plug 450, thearea of piston 440, the area of the annular surface of rim 433, and thepressure of the fluid within first chamber 439. A net force (e.g.,pre-load, biasing force, pilot force, offset force, etc.) is generatedby the difference between the force of the pressure within springchamber 444 engaging plug 450 and the force of the pressure within theintermediate chamber 446 engaging plug 450. The net force is transmittedto the gate 430 and is overcome by the force generated by the hydraulicfluid engaging the annular surface of rim 433. Such force generated bythe hydraulic fluid slides the gate 430 away from first chamber 439thereby opening the variable flow orifice. Such a system providesdifferential damping that varies with the pressure within the springchamber 444 (e.g., based on a loading condition of the vehicle) and thepressure of the hydraulic fluid. According to an exemplary embodiment,the valve assembly 420 includes a buffer that reduces pressurefluctuations within spring chamber 444 (e.g., due to compression of ahigh pressure gas spring as the vehicle encounters a positive ornegative obstacle, etc.).

Referring next to the exemplary embodiment shown in FIGS. 13A-16D, adamper assembly 500 includes a damper, shown as a hydraulic damper 502.The hydraulic damper 502 includes a tubular (e.g., cylindrical, etc.)sidewall, shown as a housing 504, a pair of caps 506 and 508. Thehousing 504 and the caps 506 and 508 define an inner volume. The innervolume of the hydraulic damper 502 is separated into a first chamber(e.g., compression chamber, jounce chamber, etc.) and a second chamber(e.g., extension chamber, rebound chamber, etc.). The chambers areseparated by a piston that is slidable within inner volume of thehydraulic damper 502. Translation of the piston within the hydraulicdamper 502 increases or decreases the volume of the first chamber andthe second chamber, thereby forcing hydraulic fluid flow along hydrauliccircuits through a first port and a second port, respectively. Accordingto an exemplary embodiment, the first port and the second port aredefined within the end cap 506. According to an alternative embodiment,one or both of the first port and the second port are defined within thecap 508.

The damper assembly 500 further includes a valve block, shown as valveassembly 520, coupled to the hydraulic damper 502. The valve assembly520 includes a pair of inlet ports 526 a and 526 b. With the valveassembly 520 coupled to the hydraulic damper 502, the inlet openings 526a and 526 b are in fluid communication with the first port and thesecond port of the hydraulic damper 502. According to the exemplaryembodiment shown in FIGS. 13A-13C, the valve assembly 520 is coupled tothe cap 506 of the hydraulic damper 502 such that the inlet openings 526a and 526 b are aligned with and directly abut the first port and secondport of the hydraulic damper 502. According to an alternativeembodiment, the openings 526 a and 526 b are otherwise coupled to thefirst port and second port of the hydraulic damper 502 (e.g., with aconduit, hose, pipe, etc. extending between the hydraulic damper 502 andthe valve assembly 520). The valve assembly 520 further includes a pairof outlet ports coupled to outlet fittings 528 a and 528 b.

As shown in FIG. 16A-16B, the body 522 defines a pair of fluid paths 524a and 524 b (e.g., flow paths, fluid circuits, etc.). The first fluidpath 524 a extends from the inlet opening 526 a to the outlet fitting528 a. The second fluid path 524 b extends from the inlet opening 526 bto the outlet fitting 528 b. According to an exemplary embodiment, thevalve assembly includes flow controllers that damp the flow of fluidalong the fluid flow paths 524 a and 524 b. The components of the flowcontrollers are arranged such that the body 522 is compact therebyreducing the overall size of the damper assembly 500 and facilitatingthe installation of the damper assembly 500 in a vehicle suspensionsystem.

Referring to FIGS. 15B and 16A-B, the valve assembly 520 includes a flowcontroller, shown as a variable flow orifice that includes a gate, shownas gate 530. The gate 530 is slidably coupled within the body 522. Avariable flow orifice is provided along each of the fluid paths 524 aand 524 b to regulate the flow of a fluid (e.g., hydraulic fluid)through the fluid paths 524 a and 524 b. Hydraulic fluid enters thevalve assembly 520 from the hydraulic damper 502 (e.g., from either thefirst chamber or the second chamber) through either of the inlets 526 aor 526 b. The fluid passes through inlet passages 539 a and 539 b,through check valves 580 a and 580 b, and through a pair of inserts 536a and 536 b.

As shown in FIG. 15A-15B, the gate 530 includes a hollow portion formedby a tubular sidewall 532 that receives a protruding portion 538 of aninsert 536. The fluid passes through the insert 536 b and engages theannular end surface of the tubular sidewall 532 to overcome a biasingforce and displace the gate 530 away from the insert 536 until anopening 534 formed in the tubular sidewall 532 overlaps an interfaceportion 525 of the body 522. The hydraulic fluid then flows through thepassage 525 and out of the valve assembly 520 through the outlet fitting528 b. Fluid flowing along the first fluid path 524 a similarly passesthrough a flow controller and out of the valve assembly 520 through theoutlet fitting 528 a.

The biasing force is applied to the flow controllers by a gas in anintermediate chamber acting on the gate 530 in a manner similar to theflow controller of the valve assembly 520 described above. The biasingforce on the gate is determined by the gas pressure in an intermediatechamber, a gas pressure in a spring chamber in fluid communication witha high pressure gas source (e.g., a high pressure gas spring), and thegeometry of a plunger separating the intermediate chamber from the firstchamber.

According to an exemplary embodiment, an intermediate chamber 546 b isin fluid communication with the gate 530 of the second flow controllerand is formed by a series of passages in the body 522 closed by plugs582 b. The intermediate chamber 546 b is supplied with pressurized gasthrough a port 547 b. An intermediate chamber 546 a is in fluidcommunication with the gate of the first flow controller and is formedby a series of passages in the body 522. The intermediate chamber 546 ais supplied with pressurized gas through a port 547 a. The intermediatechambers 546 a and 546 b are charged to a specified preset pressure(e.g., with nitrogen gas). According to an exemplary embodiment, theintermediate chambers 546 a and 546 b are charged to a preset pressureof between two and three hundred pounds per square inch.

The intermediate chamber 546 a is also in fluid communication with aplug 550 a that separates the intermediate chamber 546 a from a springchamber 544 a. The plug 550 a slidably engages an insert 560 a coupledto the body 522. The intermediate chamber 546 b is in fluidcommunication with a plug 550 b that separates the intermediate chamber546 b from a spring chamber 544 b. The plug 550 b slidably engages aninsert 560 b coupled to the body 522. The spring chambers 544 a and 544b are in fluid communication with a pressurized source (e.g. a highpressure gas spring) through a spring pilot 545.

By applying the biasing force to the flow controllers with a pressurizedgas, the flow controllers do not need to be coaxial with or in closeproximity to the plugs 550 a and 550 b and the spring chambers 544 a and544 b. As shown in FIGS. 13A-16D, the plugs 550 a and 550 b arepositioned within the body 522 in an orientation and location thatreduces the size of the valve assembly 520. According to an alternativeembodiment, the spring chambers 544 a and 544 b and the intermediatechambers 546 a and 546 b are formed in another valve body coupled to thebody 522 either directly or with a rigid or flexible conduit (e.g.,hose, tube, pipe, etc.) extending between the valve body and body 522.

According to an exemplary embodiment, dampers such as the damperassemblies 200, 300, 400, and 500 are configured to functionindependently as a part of a vehicle suspension system. Such damperassemblies may include a conduit coupling the chambers on opposing sidesof a damping piston (e.g., the compression chamber may be coupled to anextension chamber) to provide a flow path for the compressed fluid. Anintermediate accumulator may be positioned between the chambers toreduce the temperature, prolong the life of the fluid, or apply apressure to prevent cavitation. According to the exemplary embodimentshown in FIG. 17, a suspension system 800 includes dampers positioned onopposing lateral sides of the vehicle that are cross-plumbed in awalking beam configuration thereby providing anti-roll functionality. Asshown in FIG. 17, the suspension system 800 includes a first damper 810and a second damper 820. First damper 810 and second damper 820 eachinclude a manifold block, shown as manifold 812 and manifold 822,respectively. As shown in FIG. 17, a first hose 832 and a second hose834 couple manifold 812 to manifold 822. According to an exemplaryembodiment, retraction of first damper 810 (e.g., due to a correspondingwheel end impacting a positive obstacle) increases the pressure of afluid within a compression chamber (e.g., a chamber positioned between apiston and a lower end cap of first damper 810). The pressurized fluidflows through hose 834, which is in fluid communication with anextension chamber (e.g., a chamber positioned between a piston andmanifold 822) of first damper 810. According to an exemplary embodiment,the cross-plumbed arrangement shown in FIG. 17 improves roll stiffnessfor a vehicle.

It is important to note that the construction and arrangement of theelements of the systems and methods as shown in the exemplaryembodiments are illustrative only. Although only a few embodiments ofthe present disclosure have been described in detail, those skilled inthe art who review this disclosure will readily appreciate that manymodifications are possible (e.g., variations in sizes, dimensions,structures, shapes and proportions of the various elements, values ofparameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter recited herein. Forexample, elements shown as integrally formed may be constructed ofmultiple parts or elements. The position of elements may be reversed orotherwise varied, and the nature or number of discrete elements orpositions may be altered or varied. It should be noted that the elementsand/or assemblies of the components described herein may be constructedfrom any of a wide variety of materials that provide sufficient strengthor durability, in any of a wide variety of colors, textures, andcombinations. Accordingly, all such modifications are intended to beincluded within the scope of the present invention. The order orsequence of any process, logical algorithm, or method steps may bevaried or re-sequenced according to alternative embodiments. Othersubstitutions, modifications, changes, and omissions may be made in thedesign, operating conditions, and arrangement of the preferred and otherexemplary embodiments without departing from scope of the presentdisclosure or from the spirit of the appended claims.

The invention claimed is:
 1. A valve assembly for a vehicle suspensionsystem, the valve assembly comprising: a valve body defining: an inletport; an outlet port; a first chamber connected to the inlet port andthe outlet port; and a second chamber; a divider positioned to seal thefirst chamber from the second chamber; a flow controller positionedwithin the first chamber, the flow controller including: a diffusercoupled to an interior wall of the first chamber such that the diffuseris fixed, the diffuser defining a first plurality of fluid passages; apiston coupled to the diffuser, the piston spaced from the diffuser suchthat an intermediate chamber is defined therebetween, the pistondefining a second plurality of fluid passages; and a shim stack coupledto the piston on a side of the piston opposite the diffuser; and aplunger including: a piston positioned within the second chamber; a rodextending from the piston, through the divider, and into the firstchamber; and an engagement member coupled to the rod and positioned tovariably engage the shim stack based on a pressure within the secondchamber.
 2. A valve assembly for a vehicle suspension system, the valveassembly comprising: a valve body defining: an inlet port; an outletport; a first chamber connected to the inlet port and the outlet port;and a second chamber; a flow controller slidably positioned within thefirst chamber, the flow controller defining a passage; and a plugslidably positioned between the first chamber and the second chamber,the plug spaced from the flow controller such that an intermediatechamber is defined between the plug and the flow controller, theintermediate chamber filled with a gas; wherein a size of the passageand, therefore, a flow rate through the passage varies based on aposition of the flow controller; wherein a position of the plug isrepositionable based on a pressure within the second chamber; whereinthe position of the flow controller is repositionable based on theposition of the plug; and wherein, as the plug moves, the plug interactswith the gas such that the gas provides a biasing force to the flowcontroller to reposition the flow controller.
 3. The valve assembly ofclaim 2, wherein the valve body defines a passage interface thatinteracts with the passage of the flow controller, and wherein thepassage interface variably engages a portion of the passage based on theposition of the flow controller, which manipulates the size of thepassage.
 4. The valve assembly of claim 2, wherein the passage has avariable shape, the variable shape being triangular, trapezoidal,ovular, or semi-circular.